Rear noise- seems to be CV joint, or a wheel bearing.

[TheRedGlacier]

Hey guys, I've had the rear wahwahwahwah noise for awhile now, and it is still getting slightly louder by the day. It even vibrates some interior pieces enough that THEY make noise. Haha. So, up until I recently, I was positive my wheel bearing was shot, well for the past few weeks, the same area of the car (rear driver side) makes a galloping rotating click/clunk noise at low speeds, and is consistent with road speed. Turning the steering wheel right makes the noise go away, and most of the vibration. Turning to the left, makes it worse. I had a look under the car, and it would appear I have fluid of some sort on the top of the exhaust, above the inner CV, and on the very back of the axle (going into the differential). I'm not positive this is axle grease however. I had my friend tag along in the car yesterday, and he said it seems like it could be a bad cv joint back there, as a wheel bearing would not have that galloping noise. So he advised me to replace the axle or the joint, before redoing the wheel bearing. Appears to be no play in the tire.

Car is a 2001 A4 quattro 5 Speed.
(On that note, I found a crude, step by step guide for removing the rear axle. It mentions it is for 1996-2000 A4 and Passats. I'd assume 2001 is the same?)





(I'm sorry, that's the best I could get right now.)

[seanf86]

looks like gear oil from your rear diff, if its really low on fluid the noise could be coming from your rear diff as it could be trashed.

[TheRedGlacier]

I thought of that possibility, but the noise only comes from the driver's side, which wouldn't make sense.

[seanf86]

I'm gonna say wheel bearing then since the CV's in the back don't really rotate side to side like the front and turning the front wheel side loads the bearing and the CV joint doesn't turn, jack the car up and spin each back wheel, it'll be evident pretty quick if its a bad bearing.

[Davdraco1]

'Ive had both rear wheel bearings go bad since i've owned the car. It sounds like the most annoying hum ever. the whole cars hums. By the way you described the noise from which direction you turn, it should be from the passenger side since that's the side with the load when you turn left. Axles are like 40$ from rockauto and i paid 8$ for my last wheel bearing from rockauto. That grease could be a bad diff seal, cheap and easy to replace. you'll need new diff oil. Or it could be the CV on the axle itself, either way, shouldn't cost too much. Good luck.

[TheRedGlacier]

I appreciate the help guys. I got back on the ground with.the rain gone, and I noticed the tire BARELY wobbles. I could only feel it. But it was only in a small spot from the back. Could feel everywhere side to side diagonally from the front. But I need to check the other rear in case the tire is wobbling on the rim that much. Everywhere else it stayed in perfect position. Definitely gear oil leaking. So I'll have to get on that soon as well.

Edit: other side wobbles less, out of gear, brake engaged. But no noise associated with the shaking, whereas the driver's side was making a squeaky wobble, the passenger side is silent, except for the noise of the wheel rotating.